**4. Limitations of biopesticides**

Because of a number of factors, biopesticides are not widely utilized as a pest and disease management alternative, despite the fact that they offer many benefits, including the preservation of the environment and the safety of food for human consumption. For the component compounds to be effective in field settings, high dosages of the compounds are required [67]. The emerging evidence revealed that the biopesticides isolated from plants have to face more challenges regarding activity because they are extracted from plants that also contain several other bioactive compounds that could change their chemical properties. Moreover, the utilization of organic compounds as a solvent for the extraction of pesticides is involved in environmental pollution through their disposal. It was also found that biopesticides have a short shelf life that is associated with a high biodegradability rate. In addition to botanical pesticides, microbial pesticides could prove to be better pesticides for a limited type of pest in the field, but they only showed activity against one type of pest, that is one of the biggest disadvantages of microbial pesticides. Furthermore, other environmental factors such as desiccation, heat, light, and UV reduce the activity of microbial pesticides, resulting in continuous crop destruction [68].

The number of bioactive compounds present in plants and the kind of habitat in which they develop is influenced by the environment in which they are grown. Furthermore, the diversity of plants and their differences have an impact on the amount and kind of active chemicals contained in them, resulting in differences in how they respond to illnesses [69]. The quality of plant extracts, on the other hand, varies depending on the extraction method employed. It may be difficult to get the appropriate active and inert components ratios during the formulation process in certain instances. Aside from that, there are no established processes for preparation or assessment of efficacy, especially in field situations when time is of the essence [70]. However, although *in vitro* studies provide positive results, field outcomes are often inconsistent, in part due to the short shelf life of source materials and, in certain instances, the low quality of source materials and preparation methods. In order to use predatory biopesticides effectively, it is essential to do a thorough assessment of the host crops and their dispersal capacities. A manual application may be prohibitively expensive on small acreages because of the time commitment required to guarantee adequate crop coverage and exposure length. In order for products to be registered, data on chemistry, toxicity, packaging, and formulation must be supplied, which is not always the case in the pharmaceutical business [71].

#### **5. Nanotechnology**

From 1959 to 1960, developments in nanotechnology and nanoscience have been made to explore the synthesis and role of nano-particles prior to using them for different biomedical applications. Norio Taniguchi, a professor at Tokyo University of Science, made several successful attempts to synthesize nanometer-sized semiconductors in 1974. Later, it laid the foundation for research to perform experimentation on different types of nano-particles and nanocomposites. Nano-particles are found naturally in plants such as algae in the form of superoxide nano-particles and insects in the form of nanostructures. Nano-particles can be synthesized through physical, chemical, and biological methods [72].

Nano-particles fabricated via physical, chemical, and biological methods are classified by their chemical composition, Nanoparticles in the form of metals such as Cu, Fe, Zinc, Au and in the form of oxides such as ZnO, CuO, AlO, in the form of

#### *Nano-Biopesticides as an Emerging Technology for Pest Management DOI: http://dx.doi.org/10.5772/intechopen.101285*

semiconductors such as ZnS, CdS, ZnSe, carbon-based nano-particles in the form of graphene, diamond, fullerenes, in the form of silicates such as nano clays, in the form of nano-particles based on dendrite with long chains of fibers [73]. Different nano-particles are divided into different dimensions on the basis of their application in different biomaterials. The one-dimensional object possesses thin layers and fine surfaces. Second-dimensional possesses the wires with excellent flexibility and long tubes. Third-dimensional materials can be synthesized from metal oxides through physical and biological methods. These dimensions of the nano-particles have different applications in the fields of agriculture, medical, pharmaceuticals, pest management, and different industrial sectors [72].
